comparative phylogeography reveals host generalists, specialists and cryptic diversity: hexabothriid, microbothriid and monocotylid monogeneans from rhinobatid rays in southern australia.the phylogeography and host specificity of three monogenean species infecting different sites on the southern fiddler ray, trygonorrhina fasciata (rhinobatidae) in south australia (sa) were studied: branchotenthes octohamatus (hexabothriidae: gills), calicotyle australis (monocotylidae: cloaca) and pseudoleptobothrium aptychotremae (microbothriidae: skin). five rhinobatid species (aptychotrema vincentiana, t. fasciata, trygonorrhina sp. a, aptychotrema rostrata and rhinobatos typus) with distrib ...200818621052
natural outbreak of streptococcus agalactiae (gbs) infection in wild giant queensland grouper, epinephelus lanceolatus (bloch), and other wild fish in northern queensland, australia.ninety-three giant queensland grouper, epinephelus lanceolatus (bloch), were found dead in queensland, australia, from 2007 to 2011. most dead fish occurred in northern queensland, with a peak of mortalities in cairns in june 2008. in 2009, sick wild fish including giant sea catfish, arius thalassinus (rüppell), and javelin grunter, pomadasys kaakan (cuvier), also occurred in cairns. in 2009 and 2010, two disease epizootics involving wild stingrays occurred at sea world marine aquarium. necropsy ...201222324342
inter- and intraspecific variation in the distribution and number of pit organs (free neuromasts) of sharks and rays.the distribution of pit organs (free neuromasts) has previously been documented for several species of pelagic sharks, but is relatively poorly known for rays and bottom-dwelling (demersal) sharks. in the present study, the complete distribution of pit organs was mapped in the demersal sharks heterodontus portusjacksoni, orectolobus maculatus, hemiscyllium ocellatum, chiloscyllium punctatum, and asymbolus analis, and the rays rhinobatos typus, aptychotrema rostrata, trygonorrhina sp. a, raja sp. ...200312616576
a radical approach to beating hypoxia: depressed free radical release from heart fibres of the hypoxia-tolerant epaulette shark (hemiscyllum ocellatum).hypoxia and warm ischemia are primary concerns in ischemic heart disease and transplant and trauma. hypoxia impacts tissue atp supply and can induce mitochondrial dysfunction that elevates reactive species release. the epaulette shark, hemiscyllum ocellatum, is remarkably tolerant of severe hypoxia at temperatures up to 34 °c, and therefore provides a valuable model to study warm hypoxia tolerance. mitochondrial function was tested in saponin permeabilised ventricle fibres using high-resolution ...201221748398
hypoxia tolerance in elasmobranchs. i. critical oxygen tension as a measure of blood oxygen transport during hypoxia exposure.the critical o(2) tension of whole-animal o(2) consumption rate (m(o2)), or p(crit), is the water p(o2) (pw(o(2))) at which an animal transitions from an oxyregulator to an oxyconformer. although p(crit) is a popular measure of hypoxia tolerance in fishes because it reflects the capacity for o(2) uptake from the environment at low pw(o(2)), little is known about the interrelationships between p(crit) and blood o(2) transport characteristics and increased use of anaerobic metabolism during hypoxi ...201222162857
hypoxia tolerance in elasmobranchs. ii. cardiovascular function and tissue metabolic responses during progressive and relative hypoxia exposures.cardiovascular function and metabolic responses of the heart and other tissues during hypoxia exposure were compared between the hypoxia-tolerant epaulette shark (hemiscyllium ocellatum) and the hypoxia-sensitive shovelnose ray (aptychotrema rostrata). in both species, progressive hypoxia exposure caused increases in stroke volume and decreases in heart rate, cardiac output, cardiac power output (cpo, an assessment of cardiac energy demand) and dorsal aortic blood pressure, all of which occurred ...201222162858
electric field detection in sawfish and shovelnose the aquatic environment, living organisms emit weak dipole electric fields, which spread in the surrounding water. elasmobranchs detect these dipole electric fields with their highly sensitive electroreceptors, the ampullae of lorenzini. freshwater sawfish, pristis microdon, and two species of shovelnose rays, glaucostegus typus and aptychotrema rostrata were tested for their reactions towards weak artificial electric dipole fields. the comparison of sawfishes and shovelnose rays sheds light ...201222848543
functional implications of ontogenetically and sexually dimorphic dentition in the eastern shovelnose ray, aptychotrema rostrata.unlike other elasmobranchs, batoids exhibit sexually dimorphic dentition. the functional implications of such dentition, however, remain understudied. for the present study, ontogenetic and sexual dimorphism in tooth and jaw structure, together with the functional implications of this dimorphism, were determined in the eastern shovelnose ray, aptychotrema rostrata. sexually dimorphic dentition and jaw structure was first observed in sub-adult age classes, with males developing a pronounced lower ...201424072800
reproductive parameters of rhinobatid and urolophid batoids taken as by-catch in the queensland (australia) east coast otter-trawl fishery.reproductive variables are provided for batoids regularly taken as by-catch in the east coast otter-trawl fishery on the inner-mid continental shelf off the south-east and central coasts of queensland, australia. total length at maturity (lt50 and 95% c.i.) for the eastern shovelnose ray aptychotrema rostrata was 639·5 mm (617·6-663·4 mm) for females and 597·3 mm (551·4-648·6 mm) for males. litter size (n = 9) ranged from nine to 20 (mean ± s.e. = 15·1 ± 1·2). this species exhibited a positive l ...201627238204
multiple cone visual pigments and the potential for trichromatic colour vision in two species of elasmobranch.elasmobranchs (sharks, skates and rays) are the modern descendents of the first jawed vertebrates and, as apex predators, often occupy the highest trophic levels of aquatic (predominantly marine) ecosystems. however, despite their crucial role in the structure of marine communities, their importance both to commercial and to recreational fisheries, and the inherent interest in their role in vertebrate evolution, very little is known about their visual capabilities, especially with regard to whet ...200415579554
comparative visual function in elasmobranchs: spatial arrangement and ecological correlates of photoreceptor and ganglion cell distributions.the topographic analysis of retinal ganglion and photoreceptor cell distributions yields valuable information for assessing the visual capabilities and behavioral ecology of vertebrates. this study examines whole-mounted retinas of four elasmobranch species, the ornate wobbegong, orectolobus ornatus; the whitetip reef shark, triaenodon obesus; the epaulette shark, hemiscyllium ocellatum; and the east australia shovelnose ray, aptychotrema rostrata, for regional specializations mediating zones of ...200818606042
the role of olfaction throughout juvenile development: functional adaptations in elasmobranch species, a group known for their highly-developed sense of smell, were examined for developmental changes in the number of olfactory lamellae, the size of the surface area of the sensory olfactory epithelium and the mass of both the olfactory rosettes (primary input to the cns), and the olfactory bulbs. within each species, juveniles possessed miniature versions of the adult olfactory organs, visually not distinguishable from these and without any obvious structural difference ...201019941378
description of paeon asymboli n. sp. (copepoda: sphyriidae), parasitic on asymbolus spp. (catsharks) and a new host record for p. australis kabata, 1993.paeon asymboli n. sp. (copepoda: sphyriidae) is described and illustrated from two female specimens taken from the gills of a grey spotted catshark asymbolus analis (ogilby) and an orange spotted catshark a. rubiginosus (last, gomon & gledhill) (scyliorhinidae) from off southeastern queensland, australia. the key features for identification are: a pear-shaped trunk, longer than it is wide, along with a cephalothorax characterised by two large ventral papillae, projecting laterally and supporting ...200314707509
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